As far as the background of the present invention is concerned, optically active spiro-quaternary ammonium salts (A) through (N), which are collectively represented by the following formula (15), are known:
where    R12=a hydrogen atom and X−=a bromide ion (Compound (A));    R12=a phenyl group and X−=a bromide ion (Compound (B));    R12=a β-naphthyl group and X−=a bromide ion (Compound (C));    R12=a 3,4,5-trifluorophenyl group and X−=a bromide ion (Compound (D));    R12=a 3,5-bistrifluoromethylphenyl group and X−=a bromide ion (Compound (E));    R12=a 3,5-bis(3,5-bistrifluoromethylphenyl)phenyl group and X−=a bromide ion (Compound (F);    R12=a 3,5-bis-tert-butylphenyl and X−=a bromide ion (Compound (G));    R12=a 3,5-bis(3,5-bis-tert-butylphenyl)phenyl group and X−=a bromide ion (Compound (H));    R12=a β-naphthyl group and X−=a thiocyanic acid ion (Compound (I));    R12=a β-naphthyl group and X−=a hydrogen sulfate ion (Compound (J));    R12=a 3,5-bistrifluoromethylphenyl group and X−=a thiocyanic acid ion (Compound (K));    R12=a 3,5-bistrifluoromethylphenyl group and X−=a hydrogen sulfate ion (Compound (L));    R12=a 3,4,5-trifluorophenyl group and X−=a thiocyanic acid ion (Compound (M)); and    R12=a 3,4,5-trifluorophenyl group and X−=a hydrogen sulfate ion (Compound (N)) (See, for example, Patent Article No. 1 for Compounds (A) through (D), Non-Patent Article No. 1 for Compounds (E) and (F), Non-Patent Article No. 2 for Compounds (G) and (H), and Patent Article No. 2 for Compounds (I) through (N)).
Also, optically active spiro-quaternary ammonium salts (O) and (P), which are collectively represented by the following formula (16), are known:
where    R13=a hydrogen atom and X−=a bromide ion (Compound (O)); and    R13=a β-naphthyl group and X−=a bromide ion (Compound (P)) (See Patent Article No. 3).
Furthermore, optically active spiro-quaternary ammonium salts (Q), (R), and (S), which are collectively represented by the following formula (17), are known:
where    R14=a β-naphthyl group, R15=a hydrogen atom, and X−=a bromide ion (Compound(Q);    R14=a 3,5-diphenylphenyl, R15=a hydrogen atom, and X−=a bromide ion (Compound (R)); and    R14=a 3,5-diphenylphenyl group, R15=a phenyl group, and X−=a bromide ion (Compound (S)) (See Patent Article No. 3).
Still further, optically active spiro-quaternary ammonium salts (T), (U), and (V), which are collectively represented by the following formula (18), are known:
where    R16=R17=a phenyl group and X−=a bromide ion (Compound (T));    R16=a phenyl group, R17=a hydrogen atom, and X−=a bromide ion (Compound (U)); and    R16=R17=a 3,5-diphenylphenyl group and X−=a bromide ion (Compound (V)) (See Non-Patent Article No. 3).
Some of Compounds (A) through (V), for example Compound (D), are highly reactive and stereoselective. Nonetheless, the asymmetric structure of these compounds results in as many as 13 to 16 different steps involved in the synthesis of the catalysts when commercially available optically active 1,1-bi-2-naphthol is used as the starting material.
Still further, optically active spiro-quaternary ammonium salts (W), (X), (Y), and (Z), which are collectively represented by the following formula (19), are known:
where    R18=R19=a phenyl group and X−=a bromide ion (Compound (W));    R18=a phenyl group, R19=a hydrogen atom, and X−=a bromide ion (Compound (X));    R18=R19=a 3,5-diphenylphenyl group and X−=a bromide ion (Compound (Y)); and    R18=a 3,5-diphenylphenyl group, R19=a hydrogen atom, and X−=a bromide ion (Compound (Z)) (See, for example, Non-Patent Article No. 4). Since the two binaphtyl structures in these compounds are identical to each other, the number of the steps involved in the synthesis of these catalysts is decreased to 8 to 11 steps.
In terms of catalytic performance, these catalysts show high reactivity and high selectivity of 90% or above toward certain substrates when used in the asymmetric alkylation of glycine derivatives as described in the non-patent article. However, the catalysts have been proved to show decreased reactively and selectivity toward some substrates such as ethyl iodide.
Of all the compounds represented by the following formula (1):
only those in which the substituents on the aromatic rings are either hydrogen or carbon atoms are known. In addition, no compounds are known that are represented by the formula (1) with silicon atoms or silicon-containing compounds directly bound to the aromatic rings.
When optically active quaternary ammonium salts are used as phase-transfer catalysts in the production of optically active α-amino acid derivatives, the catalysts may be recovered afterwards for recycle. In one technique, this is done by neutralizing the aqueous phase with an acid after separation, extracting the aqueous phase with an organic solvent, and then purifying the extract by silica gel column chromatography (Non-Patent Article No. 5). While this technique is advantageous in that the activity of the recycled catalysts is retained, the recovery of the catalyst is only 72% and the technique involves many steps. For this reason, improvement in the recovery of the catalyst is required. Also, the process for recovering catalysts must be simplified enough to be used in industrial applications.
A much simpler approach to recover catalysts involves the use of a compound represented by the following formula (20):

This compound comprises an ammonium salt derivative of an optically active alkaloid (e.g., quinine, quinidine, cinchonine, and cinchonidine) bound to a polymer such as polystyrene and polyethylene glycol and is suitable for use as a chiral phase-transfer catalyst in the production of optically active α-amino acid derivatives (See Non-Patent Articles 6-8 for examples in which the polymer is introduced at the position ‘A’, Non-Patent Article 7 for an example in which the polymer is introduced at the position ‘B’, and Non-Patent Article No. 9 for an example in which the polymer is introduced at the position ‘C’.).
However, introduction of the polymer moiety may result in a significant decrease in the selectivity of the catalyst (See, for example, Non-Patent Article No. 9). Even many of the catalysts that retain high stereoselectivity of 90% ee or above have not been shown to retain the catalytic performance when recycled following recovery (See, for example, Non-Patent Articles 7 and 8). Although no data is presented, only one example of practically recyclable catalysts is reported. In this case, a significant reduction of the selectivity is also experienced in this example when a different substrate is used (See, for example, Non-Patent Article No. 6).
As optically active quaternary ammonium salts in which the backbone structure contains a fluorine atom as a C—F bond, alkaloid derivatives incorporating a fluorine-substituted benzyl group are known (See, for example, Non-Patent Articles 10 and 11). Also, optically active ammonium catalysts having such substituents as a 4-fluorophenyl group and a 3,4,5-trifluorophenyl group (See, for example, Non-Patent Article No. 12), a 3,5-bis(trifluoromethyl)phenyl group or a 3,5-bis{3,5-bis(trifluoromethyl)phenyl}phenyl group (See, for example, Non-Patent Article No. 13) are known as optically active quaternary ammonium salt derivatives having a chiral axis originating from binaphthyl.
However, each of these compounds contains fluorine atoms in the form of 1 to 3 fluorine substituents on the benzene ring or in the form of 1 to 8 trifluoromethyl groups: No optically active quaternary ammonium salts have been known to date that contain fluorine atoms in the form of perfluoro groups, or substituents consisting of two or more carbon atoms with all the hydrogen atoms substituted with fluorine atoms.
Different perfluoro alkyl-containing optically active asymmetric catalyst ligands are known, including axially chiral binaphthol derivatives (See, for example, Non-Patent Articles No. 14-18), optically active salen derivatives (See, for example, Non-Patent Articles No. 19-22), optically active ephedrine derivatives (See, for example, Non-Patent Article No. 23), and optically active aminothiolates (See, for example, Non-Patent Article No. 24). Each of these compounds is used in the synthesis of optically active compounds different from the compounds of the present invention. Attempts for recovery and recycle have been made for some of the compounds.
However, except for the asymmetric protonation agents used in stoichiometric amounts (Non-Patent Article 14), each compound has to be catalytically prepared through the formation of oxygen-metal bonds or complexes: No optically active organic catalysts are known that themselves serve as an asymmetric catalyst. In particular, no optically active quaternary ammonium salts are known that contain perfluoro alkyl groups consisting of two or more carbon atoms. Nor are any examples known of the use of the salts as asymmetric catalysts or as phase-transfer catalysts. No examples are known in which the phase transfer catalytic reaction is carried out in a three-phase system consisting of organic, aqueous and fluorous phases, nor are any examples described of the use of fluorous solvents to separate/purify the salts or to recover only the catalyst from the catalyst-containing mixture remaining after the reaction. No examples are known of recovering the salts to serve as catalysts in a substantially quantitative manner, nor are any examples known in which the salts are recovered in a separate phase of a fluorous solvent and the recovered salts are recycled as an asymmetric catalyst in the same reaction, and which demonstrate that the performance of the catalyst as measured by the reactivity and stereoselectivity are retained.
[Patent Article No. 1] Japanese Patent Laid-Open Publication No. 2001-48866
[Patent Article No. 2] Japanese Patent Laid-Open Publication No. 2002-173492
[Patent Article No. 3] Japanese Patent Laid-Open Publication No. 2002-326992
[Non-Patent Article No. 1] K. Maruoka et. al., Angew. Chem. Int. Ed. 2002, 41, 4542-4544
[Non-Patent Article No. 2] K. Maruoka et. al. Angew. Chem. Int. Ed. 2003, 42, 579-582
[Non-Patent Article No. 3] K. Maruoka et. al., Tetrahedron Lett. 2003, 44, 3313-3316
[Non-Patent Article No. 4] K. Maruoka et. al. Tetrahedron: Asymm. 2003, 14(12), 1599-1602
[Non-Patent Article No. 5] K. Maruoka et. al., Tetrahedron Lett. 2000, 41, 8339-8342
[Non-Patent Article No. 6] R. Chinchilla et. al., Tetrahedron: Asymm., 2000, 11, 3277-3281
[Non-Patent Article No. 7] D. Cahard et. al., Synthesis, 2001, 11, 1742-1746
[Non-Patent Article No. 8] D. Cahard et. al., Tetrahedron: Asymm., 2001, 12, 983-986
[Non-Patent Article No. 9] M. Benaglia et. al., Tetrahedron: Asymm., 2003, 14, 461-467
[Non-Patent Article No. 10] H. G. Park et. al., Org. Lett., 2002, Vol. 4, No. 24, 4245-4248
[Non-Patent Article No. 11] B. R. Cho et. al., J. Org. Chem., 1987, 52, 4752-4756
[Non-Patent Article No. 12] Keiji Maruoka et. al., J. Am. Chem. Soc., 2003, 125, 5139-5151
[Non-Patent Article No. 13] K. Maruoka et. al., J. Am. Chem. Soc., 2003, 125, 2054-2055
[Non-Patent Article No. 14] S. Takeuchi et. al., Tetrahedron, 2000, 56, 351-356
[Non-Patent Article No. 15] S. Takeuchi et. al., Tetrahedron, 2002, 58, 3963-3969
[Non-Patent Article No. 16] K. S. Chan et. al., Tetrahedron, 2002, 58, 3951-3961
[Non-Patent Article No. 17] D. Sinou et. al., Tetrahedron: Asymm., 2002, 13, 1449-1456
[Non-Patent Article No. 18] D. Sinou et. al., Chem. Commun., 2001, 1220-1221
[Non-Patent Article No. 19] D. Sinou et. al., Tetrahedron, 2002, 58, 3971-3976
[Non-Patent Article No. 20] G. Pozzi et. al., Eur. J. Org. Chem., 1999, 1947-1955
[Non-Patent Article No. 21] G. Pozzi et. al., Chem. Commun., 2000, 2171-2172
[Non-Patent Article No. 22] G. Pozzi et. al., Tetrahedron, 2002, 58, 3943-3949
[Non-Patent Article No. 23] S. Takeuchi et. al., Tetrahedron, 2001, 57, 5565-5571
[Non-Patent Article No. 24] G. v. Koten et. al., Org. Lett., 1999, Vol. 1, No. 6, 853-855